Re: [PATCH 06/12] gpio: Add Aspeed driver

From: Paul Gortmaker <paul.gortmaker@windriver.com>
To: Andrew Jeffery <andrew@aj.id.au>
Cc: Linus Walleij <linus.walleij@linaro.org>,
	Alexandre Courbot <gnurou@gmail.com>,
	Joel Stanley <joel@jms.id.au>,
	Mark Rutland <mark.rutland@arm.com>,
	Rob Herring <robh+dt@kernel.org>,
	Russell King <linux@armlinux.org.uk>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Jeremy Kerr <jk@ozlabs.org>,
	devicetree@vger.kernel.org,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	linux-gpio@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	Alistair Popple <alistair@popple.id.au>
Subject: Re: [PATCH 06/12] gpio: Add Aspeed driver
Date: Thu, 21 Jul 2016 16:12:44 -0400	[thread overview]
Message-ID: <CAP=VYLrJfRmKOoDWTpBrD5+iPdX6J9r609FzZ0CkzDd7vGBWyw@mail.gmail.com> (raw)
In-Reply-To: <1468994313-13538-7-git-send-email-andrew@aj.id.au>

On Wed, Jul 20, 2016 at 1:58 AM, Andrew Jeffery <andrew@aj.id.au> wrote:
> From: Joel Stanley <joel@jms.id.au>
>
> The Aspeed SoCs contain GPIOs grouped by letter, where each letter group
> contains 8 pins. The GPIO letter groups are then banked in sets of four
> in the register layout.
>
> The implementation exposes multiple banks through the one driver, and
> requests and releases pins via the pinctrl subsystem. The hardware
> supports generation of interrupts with per-pin triggers, and exposes this
> capability through an irqchip and devicetree.
>
> A number of supported features are not yet implemented: Configuration of
> interrupt direction (ARM or LPC), debouncing, and provides WDT reset
> tolerance for output ports.
>
> Signed-off-by: Joel Stanley <joel@jms.id.au>
> Signed-off-by: Alistair Popple <alistair@popple.id.au>
> Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> ---
>  arch/arm/mach-aspeed/Kconfig |   4 +
>  drivers/gpio/Kconfig         |   8 +-
>  drivers/gpio/Makefile        |   1 +
>  drivers/gpio/gpio-aspeed.c   | 456 +++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 468 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/gpio/gpio-aspeed.c
>
> diff --git a/arch/arm/mach-aspeed/Kconfig b/arch/arm/mach-aspeed/Kconfig
> index 25a0ae01429e..a52de9d3adfb 100644
> --- a/arch/arm/mach-aspeed/Kconfig
> +++ b/arch/arm/mach-aspeed/Kconfig
> @@ -6,6 +6,10 @@ menuconfig ARCH_ASPEED
>         select ASPEED_WATCHDOG
>         select MOXART_TIMER
>         select PINCTRL
> +       select GPIOLIB
> +       select GPIO_ASPEED
> +       select GPIO_SYSFS
> +
>         help
>           Say Y here if you want to run your kernel on an ASpeed BMC SoC.
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index 536112fd2466..2c21b5db09cd 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -137,6 +137,13 @@ config GPIO_ATH79
>           Select this option to enable GPIO driver for
>           Atheros AR71XX/AR724X/AR913X SoC devices.
>
> +config GPIO_ASPEED
> +       bool "Aspeed GPIO support"

Since this is a bool Kconfig...

> +       depends on (ARCH_ASPEED || COMPILE_TEST) && OF
> +       select GENERIC_IRQ_CHIP
> +       help
> +         Say Y here to support Aspeed AST2400 and AST2500 GPIO controllers.
> +

[...]

 > diff --git a/drivers/gpio/gpio-aspeed.c b/drivers/gpio/gpio-aspeed.c
> new file mode 100644
> index 000000000000..7885adc1332a
> --- /dev/null
> +++ b/drivers/gpio/gpio-aspeed.c
> @@ -0,0 +1,456 @@
> +/*
> + * Copyright 2015 IBM Corp
> + *
> + * Joel Stanley <joel@jms.id.au>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version
> + * 2 of the License, or (at your option) any later version.
> + */
> +
> +#include <linux/module.h>

...can you please get rid of module.h and all the MODULE_<xyz>
stuff and use the built in registration?   Alternatively change it to
a tristate if there is a valid use case for it to be modular.

Thanks.
Paul.
--

> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/spinlock.h>
> +#include <linux/platform_device.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/pinctrl/consumer.h>
> +
> +struct aspeed_gpio {
> +       struct gpio_chip chip;
> +       spinlock_t lock;
> +       void __iomem *base;
> +       int irq;
> +       struct irq_chip irq_chip;
> +       struct irq_domain *irq_domain;
> +};
> +